# Config Service Refactoring

## Overview
This document describes the refactoring of the configuration loading functionality in the `ConfigService` to eliminate code duplication and improve maintainability.

## Problem Identified
The `src/services/config.rs` file contained two functions that performed nearly identical configuration loading operations:

1. **`load_config()`** function (line 146)
2. **`AppConfig::load()`** method

Both functions used the same Figment configuration loading pattern:
```rust
Figment::new()
    .merge(Toml::file("config.toml"))
    .merge(Env::prefixed("SPEAR_"))
    .extract()
```

## Analysis
- **`load_config()`**: Returns `Result<SmsConfig, figment::Error>`
- **`AppConfig::load()`**: Returns `Result<AppConfig, figment::Error>`

Since `AppConfig` contains `SmsConfig` as a field, the standalone `load_config()` function was redundant. Additionally, analysis showed that `load_config()` was not being used anywhere in the codebase.

## Solution
**Removed the redundant `load_config()` function** from `src/services/config.rs` since:
1. It duplicated the functionality of `AppConfig::load()`
2. It was not being used anywhere in the codebase
3. `AppConfig::load()` provides more comprehensive configuration loading

## Code Changes

### Before Refactoring
```rust
/// Load configuration from file and environment variables
/// 从文件和环境变量加载配置
pub fn load_config() -> Result<SmsConfig, figment::Error> {
    Figment::new()
        .merge(Toml::file("config.toml"))
        .merge(Env::prefixed("SPEAR_"))
        .extract()
}

impl AppConfig {
    /// Load configuration from file and environment / 从文件和环境变量加载配置
    pub fn load() -> Result<Self, figment::Error> {
        Figment::new()
            .merge(Toml::file("config.toml"))
            .merge(Env::prefixed("SPEAR_"))
            .extract()
    }
    // ... other methods
}
```

### After Refactoring
```rust
impl AppConfig {
    /// Load configuration from file and environment / 从文件和环境变量加载配置
    pub fn load() -> Result<Self, figment::Error> {
        Figment::new()
            .merge(Toml::file("config.toml"))
            .merge(Env::prefixed("SPEAR_"))
            .extract()
    }
    // ... other methods
}
```

## Benefits of Refactoring

1. **Eliminated Code Duplication**: Removed redundant configuration loading logic
2. **Improved Maintainability**: Single source of truth for configuration loading
3. **Cleaner API**: Simplified the configuration service interface
4. **Reduced Confusion**: No more ambiguity about which function to use for configuration loading

## Testing Results
- ✅ All compilation checks passed
- ✅ Library tests passed
- ✅ Binary compilation successful
- ✅ No breaking changes introduced

## Files Modified
- `src/services/config.rs`: Removed redundant `load_config()` function

## Future Enhancements
- Consider adding more specific configuration loading methods if needed
- Implement configuration validation and error handling improvements
- Add configuration caching mechanisms if performance becomes a concern

## Conclusion
This refactoring successfully eliminated code duplication in the configuration service while maintaining all existing functionality. The codebase is now cleaner and more maintainable.